Shelf life of a Magnesium test kit?

[Neya]

I have a red sea magnesium test kit.. About 6 months old since opening. My mag is testing 1600+ (I had a violet change at about 1500, a solid blue at 1700) and I think its probably wrong. I tested twice. Maybe user error, I'll attempt again. Anyone know the shelf life on these things once opened? Expiration date on box is 1/12


background:
Ive been neglecting the tank a bit up until recently(yay GHA on all my equipment, not really on rocks), it didn't receive a water change for awhile, nor dosing of mag. I did a water change 2 weeks ago with IO Reef Crystals and added 1oz of BRS mixed (1gal container) Magnesium - Much less than required to raise it 100ppm(about 10oz). My tank is about 40gal total volume - 37gal with medium cpr aquafuge.

 

[Neya]

I found a thread recently where this same problem was had by at least 1 other person with recent red sea kits in CT.
Just a heads up to anyone using the brand

 

[The Ng Thing]

I've been having the same problem as well.

 

[Neya]

I decided to send an email to Red Sea and see what they say about the problem. Although not major, I figured its something they should know about in case its a bad lot. I will update here.

 

[The Ng Thing]

I retested today and got a slightly lower number ~1500 rather than 1600. I did a w/c last week and haven't added an Mg like I normally do. I'm still not convinced though because I rushed through the test rather than waiting the 15 sec like the directions say. If you make any head way let me know, I think I'm going to contact them too.

 

[Neya]

They finally got back to me after sending several emails.
Their reply was very much "We stand behind our chemistry" and that the results we're seeing are outside of their range and therefore must be user related not test kit related, unless we were using the old syringes (that sprayed rather than created tear drop shapes). I do have the newer syringe, yet still have crazy results.